The provision of reinforcing rings around openings in sheet material and, in particular, to sail cloth is old in the art as shown in U.S. Pat. Nos. 3,653,353; 3,683,844; 3,812,809; 3,979,798; and 3,890,695. It is the purpose of this invention to improve upon the structure shown in the aforesaid patents by providing a structure which will distribute the load as efficiently as any structure shown in the aforesaid patents, but which will be less prone to cracking and stripping under strain, which will be much lighter in weight, which can be made of a material which will not corrode and which will be less expensive to manufacture.